The Beastie
by sui-generis-47
Summary: The Doctor Ten and Rose are on another adventure. This time they land on an island full of school boys. The setting seems eerily familiar, but something isn't right. Leave it to the Doctor and his companion to not only figure it out, but get trapped in the story itself. Rated K for at least now.


**I've been wanting to do a crossover like this for so long. I hope someone actually sees it. Case you didn't read, it's the Tenth and Rose.**

"So tell me, Rose," the Doctor started as he whirled around and leaned over his TARDIS controls, "Where have you always wanted to go?"

Rose gleamed with joy as she pictured all the parts of the world- no, the universe- that could visit in that blue box. "So many places! Ancient Rome, New York City, Mount Everest, the Caribbean-"

"Patience, my dear, only one place at a time," the Doctor laughed.

"Surprise me then!" Rose told him.

"Alright then, I'm good at surprises." The Doctor's hands flew, between turning and twisting and flipping, it was hard to tell when he was doing what. That was one of the many things Rose enjoyed as she held on tight, waiting for her next adventure. As usual, the TARDIS lurched here and there, it rumbled, it shook, until it finally came to a stop with one last tug.

"So, where are we, Doctor?" asked Rose.

"Well, let's take a looky, shall we?" The Doctor popped open the door and Rose joined him to check the outside. Trees were covering the TARDIS and shadowing over their surrounding area. The ground was a deep brown dirt with shurbs of little green life popping up here and there. Rose managed to peer through some leaves into the open. Her eyes widened as she saw the white beach and inviting teal waters glistening in the sun.

"We're at the beach!" she exclaimed, partly from confusion.

"Yes, I'd say so," the Doctor agreed, examining the area with his sonic screwdriver. "But why were we sent here…"

Rose turned around. "You mean this is another one of your mission things? Can't it just be a fun thing?"

" 'Mission things' are fun things!" the Doctor told her happily with a grin. Rose smiled back like a sucker and continued to study the beach. Suddenly, a loud horn erupted and interrupted the two.

"Doctor, what's that?"

"I'm not too sure," he mumbled.

"What's with all those boys? Do you think this is a school trip or something?" The Doctor jumped at Rose's side and peered towards where she was looking.

"Aaand back in the TARDIS we go," he said, taking Rose's arm with him into the police box.

"Wait, what's going on?" she asked as he started rummaging through some of his equipment. "Do you know where we are?"

"Island. Towards the beginning of World War II. Rose, have you ever read the book, _Lord of the Flies_ in your class?" he ran off of his tongue.

"Uh, of course, for assignment yeah, why?"

The Doctor gave her a cock of his eyebrow. "No," she said incredulously. He raised his eyebrows a bit higher in that way that Rose knew exactly what he meant. "No way! That was real?"

"Sort of. There isn't really much time to explain, I just need- FOUND IT." He yanked out something that partly resembled a high-tech squirt gun. "This thing is ages old, never thought I'd have to use it-"

"What are you gonna do, get into a water fight with those boys?" Rose laughed.

"This is one of the most dangerous and powerful pieced of equipment to ever reach the Earth," he clarified.

"…Oh."

"What it does is it reverts the cells of a human, but only for a certain period of time. It's got a little bit of the TARDIS mechanism in it, but instead of keeping the body and changing the place or time, it changes the body and keeps the place or time. In lamens term, anyway."

"Okay, but why do we need it?"

"Because you and I are blending in."

"Wait, you mean you're going to use that on _me_?"

"I know it sounds dangerous but it's been used before and there's 100% accuracy of you coming out the same way and I've seen it being used it's never gone wrong and you'll be perfectly safe and I promise you I pinky pinky pinky swear," he rambled. Rose waited until he was done.

"Okay."

The Doctor's head perked up. "_Really_?" he asked, scrunching up his face in doubt.

"Yeah. If you're sure."

"Oh, I am." He flicked a few switched here and there and hoisted it up like a machine gun. "Are you ready?"

"Ready as I'll ever be," Rose laughed a bit nervously.

It was like a jet of cool water, starting with Rose's head and ending at her feet. She blinked once or twice until locking eyes with the Doctor. "I don't feel different." When she looked down, she saw her clothes fitted her strangely hung a bit limp. "Guess I look different."

"Aw, aren't you adorable!" the Doctor cried.

"Oy!"

"Sorry."

"And what about you, Doctor?"

"Well, normally I'd just have to regenerate and hope that I turn into a boy that looks about their age." Rose's young face fell. "But, there is one more thing I could try. But I'll need your help."

"Alright, what is it?" Rose asked, mesmerized by the floppiness of her sleeves.

"Go outside and find the nearest boy. You'll have to bring him in."

"What're you gonna do to him?" she asked, her eyes widening a bit.

"I just need a hair sample, that's all!" he said, twisting his face.

"Oh, I thought you were going to take a vial of his blood or something," she sighed.

"Wow. I thought you'd have gotten used to this whole thing by now," the Doctor said. Rose rolled her eyes and stepped out the door. It took her a few minutes of walking, but she managed to find a boy passing by.

"Excuse me," she said. The boy whipped around and looked at her crazily. He seemed about 13 or 14 years old.

"What are you doing here?" he asked. "When did you get here?"

"Oh, I just landed here a minute or two ago," she answered a bit shakily.

"Impossible. We didn't see a plane."

"Came in through the ocean- listen. I just needed some help with…" Rose tried hard to remember the book. None of it was easing back into her mind. All she could remember was her Literature teacher's mouth running off about some antagonist character and some knowledge and some innocent and… she was practically sleeping from boredom on the spot.

"The beast?" he asked.

"Yeah!" she cried a bit too excited to blend in. "The beast."

"There is no beast," he said. "Jack's going to kill it."

"Oh, right, right," Rose thought aloud. "Well, um, could you just check it out really quick?"

The boy seemed a bit frightened, but tried to pass it off. He resumed a straight posture and lifted his head. " 'Course. Won't be anything there."

Rose nodded. She lead him to the TARDIS, which to him obviously must have seemed outrageous. "Wait, what is this?" he asked. "Are we really in civilization? Is this a prank?"

"I, uh, I just found it here, but there's something weird inside," Rose said, trying her best to sound genuinly confused. "Look."

Tentatively, the boy opened the door. He muttered a "What the-" before Rose pushed him in.

"Ah, thank you, Rose. I was wondering what was taking so long," the Doctor said, peering from around the TARDIS controls.

"What are you going to do to me?" the boy screamed. "Tell me!"

"I can see the island has advanced pretty far already," the Doctor mumbled.

"How do you know about it?" the boy hollered.

"It's all right, you're dreaming," the Doctor said quietly. He gently took the sonic screwdriver out of his pocket and used it on the boy, low frequency. He barely said a word about the strange device before conking out on the floor. "Don't worry, only temporary, Rose," he said, already knowing what expression would be on her face.

"He's nearly crazy," she mumbled as the Doctor snatched a piece of hair from the boy's head.

" 'Fraid so. Life without civilization or some form of control can do that someone."

"Why didn't they just make one?"

"They tried. This is how it turned out," he answered. He pulled out another piece of equipment and fit in the hair somehow.

"What are you doing?" Rose asked.

"This essentially does almost what that gun did to you, but for time lords and, well frankly it's more painful."

"What? What do you mean?"

"Well you just had your cells warped from a different time period. I don't have a time period to change my cells to. I used the hair from that young boy for his sample, but the cell of a time lord is powerful. It'll compress his cell and change me, adapting a few of his characteristics, such as youthful looking traits. They're pretty universal. But I can't change into it exactly, so it'll practically be creating myself new physical traits. They'll adapt to what I look like now. Not completely the same as that boy, though. It all depends on these switches here. I'll still remain time lord, just look different, younger. But it'll only be like so for as long as that boy remains unconscious. Technically I'll still be borrowing part of his DNA, and the device can't let me use it while the boy's roaming around, that's just ridiculous."

Rose nodded, eyes wide and head blank. "Yeah, okay," she said.

"Right. So I'm just going to wrap this around my wrists and ankles and you're going to flip that switch when I say so, alright?" Rose nodded. She followed as instructed, and after a bright flash of light enveloped him, the Doctor looked like a 14 year old boy using his father's suits. Rose tried her best to stifle laughter. "What?" asked the Doctor, his hands running over his hair and face. "What is it?"

"Nothing, it's just…you as a 14 year old makes me laugh, that's all."

"Glad I amuse you, 'Rosie' ," he said with a smirk.

"Ay."

"Come on now, we've got a meeting to attend to."


End file.
